Hand brake mechanism



Nov. 2 192e.

W. H. MUSSEY HAND BRAKE MECHANISM Filed July 30. 1925 1L] m N if@ t* Fw* f/Vl/A/TR William lmwssey.

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Patented Nov. 2, 1926.

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PATENfr,l OFFICE.y

.WILLIANI I-I. IVIUSSEY, OF CHICAGO, ILLINOIS, ASSIGNOR TO PULLMAN CAR AND MAN- UFACTURINGCORPORATION, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

kHAND BRAKE MCHANISM.

. Application led July 30, 1925. Serial No.47,049.

The invention relates to devices forming part of the hand brake mechanism of railf way cars and designed for use in conjunction with the air brake rigging to which it is operatively connected.

An object of the invention is to provide mechanism to take the place of the4 usual hand brake lever in the brake rigging orn ganization and devised with means for quickly taking up the slack inthe rigging with a minimum expenditure of power during the initial stages of the braking operation until the brake shoes have come into contact with the wheels whereupon the maximum power of the mechanism becomes effective.

Another and important object is to so mount the sheave worm of the mechanism that any tendency on the part of the chain winding thereon to climb the worm threads will be overcome and excessive or objectionable lateral movements and angularities in the chain with respect to air brake cylinder and hand brake staff prevented.

In the drawing Fig. 1 is a plan view of a portioniof a railway car equipped with a brak-e arrange ment embodying the invention;

Fig. 2 is a side elevation thereof;

Fig. 3 is an enlarged view of the worm in vertical section taken on line 3.-3 of Fig. 4 looking in the direction indicated by the arrow; and

Fig. 4 is a side .elevational view of the worm with portions of the housing broken away to more clearly show the wormy construction.

In said drawing, 1() represents the underframe of a railway car equipped with the invention. An air brake cylinder 11 is secured to the underframe and connected to cylinder lever 13 thru the medium of its piston 12 in a well-known manner. Adjacent the air cylinder 11 and positioned approximately at the point occupied by the hand lever heretofore employed, I attach a housing 14, lsupporting same on the underframeA of the car by means of brackets of any approved design, that inthe drawing being made u of a base plate 16 extending the full length and width of housing 14 and secured to the center sills 9 of the underframe in conjunction with a plurality of brace bars 17 and connected to the end rails 18 of the housing by bolts 19.

Within housing'14 is fmounted a sheave worin 2O having a continuous chain vgroove 21 terminating in straight hub groove por tions 22 and 23 extending from the groove periphery tangentially to the hub 24 of the worm and at an angle to each other for a purpose to be hereinafter described.

. The worm 20 is slidably and rotatably mounted upon spindle 25 held inbearings 26 of the housing14, an-d its length is preferably proportioned to the distance between the spindle bearings 26 in order to permit suihcient movement of the worm longitudiu nally of the spindle 25 under the impetus of the winding and unwinding operations of the sheave worm chain 27 as will presently appear.` The worm 2O is formed with a chain anchorage 28at a point intermediate the ends of the chain groove 21 as best shown in Fig. 3, the anchorage being fitted with a pin 29 removably mounted in bearings 30 of the anchorage and passing through a link of chain`27 as illustrated in this iigure.

The sheave worm chain 27 is preferably continuous and wound about the worm 2O with its ends extending4 in opposite directions and operatively secured respectively to cylinder lever 18 and hand brake staff 31,/the connection to the brake staif being effected through m-edium of brake rod 32 and brake chain 33 as shown in Figs. land 2. The chain is held from displacement within chain grooves 21 of the worm by the several cross members 34 of housing 14 disposed as shown in Figs. 3 and 4. Y

In operation, Aassuming the parts to be in the brake shoe released position, to bring the shoes into braking contact with ,the wheels, the brake staff 31 is rotated to cause .a pull on chain 27' initially` traversing hub groove porti-on 22 and circumferential groove 21 on the sheave worm. IVith the chain portion leading to the brake staff` at the vhub groove position 22 and that portion leading to the cylinder lever 13 at the circumferential groove '21, Va relatively slight movement of the brake staff .end of chain 27 will cause a correspondingly increased movement of the opposite end of said chain in direct proportion to the difference inthe diameters of worin at hub and periphery thereof. With the worm 2O in its normal released position shown in Figs. 2, 3 and 4,*a pull on chain 27 will rotate the worm in the direction indicated by the arrow in Fig. 4

whereupon the chain position on Worm 2O will have shifted and the relation of its respective ends to brake staff and cylinder lever reversed; that is to say, that portion of chain 27leading to the cylinder lever and initially occupying the circumferential groove position indicated in Figs.- 2 and 3 Will have shifted to a position in hub groove 23 at the end of the Worm20,and the por,- tion leading to brake stafi7 31 originally in hub groove22 as shown in Fig. 3 will have occupied a position in the circumferential groove 21. It will `be evident that inthe changed positions of the chain portionsconnecting the cylinder lever 13 to Worm 20 and said Worm to the brake staff a relatively small pull onthe chain atthe circumference of the Worm Will effect a proportionate vincrease in the power applied at thehub .to the chain portion leading to the cylinder lever 13 and, therefore, to the Wheels through brake rods 32 and truck levers 8.

.It will be observed that the lpower initially applied to .the Worm to obtain maximum speed in the applieation of the brake shoes to theivheels has `been translated into a maximum power applied to the Wheels and exerted by the avorm. During this translation of initial speed to ultimate power `the Worm 20 Will have rotated "approximately 90O from the position indicated in Fig. 4, and the opposite portions of chain27 fwill have moved fromlthefull yline position indi-' cated at 35 and 36 in Fig. 2 to the dotted line position shown at 3'? and V38 and during this movement the cylinder vlever 13 and connected parts Will have moved to their final positions as shown in dotted lines in Figs. 1 and 2 in which position the brake shoes will have moved into `contact With the Wheels.

whereupon continued rotation of Worm Will cause the required bralre shoe pressure to vbe exerted upon .the Wheels in the -manner above outlined. f i s l It should also be noted that duringathe winding and unwind-ing movements of the chain 27 on the Worm 20, the avorm will move longitudinally of the vsupporting spindle 25 in response to the winding pressure of the chain Within the Worm groove 21` such movement bei-ng caused lby .the sidewiping of the chain due to its tendencyto climb the- Worm groove Walls. As will be obvious, the worm Will yield `to the side thrust of the chain and move longitudinally of the spindle 25 a distance corresponding to extent of the shift of the chain on thel Worm during the chain. Winding operations, and to thatextent the chain portions leading to cylinder lever 13 and brake staff 31 are prevented from assuming excessive angularities With respect to the chain grooves on. the Worm 20suflic1ent clearance being pro-- vided for that purpose as indicated at 39 in Figsl and 3.

yIt will be further noted that the tangential hub groove `22 in the position indicated in F ig. 4 ivill permit the portion of sheave ,Worm .chain 27 leading to the bral-:e staff 31 to assume a. position at thehub parallel to said groove, but upon approximately a quarter rotation of said Worm as before described the relative angularity of the tangential groove portions 22 and 23 Will Vcause groove 23 to assume a position to the right of thcspindle25 in Iligi- 4 corresponding to the roriginal' position Aof groove port-ion 22 shown4 at the left of this figure thereby permitting that portion'of .chrn 27 leading to the cylinder lever 13 to assume aposition the hub parallel to groove portion 23 as indicated at 37 in Fig. 2 and forthe purposes hereinbefore outlined.

Wh at I claim is :4-

1. In hand brake mechanism for cars coinprising la sheave avorm operatively.connected to other .elements of-thebrake organization and having hub portions, straight terminal chain .groove portionsin tangential relation to said hubs, and an intermediate circumferential groove connecting' said terminal groove portions and form-ing a continuation thereof.

2. In :hand brakemochanism for .cars .coinprising a sheave Worm operatively connected to 4.other elements of .the brake organization and provided With hub end portions, an intermediate circumferential chain groove portion, and .straight terminal groove .portions in tangential relatie-nto said hubs `and forming continuations of..said intermediate circumferential groove.

3. In hand Vbrake.mechanis1n, `a sheavo Worm havin-g a .circumferential chain groove intermediate its ends, terminal grooves forming extensions vof said intermediate groove, and hub `endportions von said Worm, said terminal grooves having y straight groove portions connecting said Vhubs and circumferential groove.

4. In hand brake niechanism.;a sheave Worm having end hubs and a circumferen tial: chain groove intermediate .said ,hubs terminating in straight groove portions tangent -to said hubs, said terminal grooveportions being arranged at an angle with rcspect to each other.

5.111 la. car bra-ke arrangement, a `hand brake mechanism comprisinga housing,

power and speed multiplying vsheave Worm rotatably mountedfin said housing and having straight relatively angular terminal grooves, and oppositely extending operating connections, said grooves becoming effective upon rotation of said Worm to respectively traverse 4said f connections.

A In Witness ,whereof I have ihereto set my hand this l27th day of July, 1925.

WILLIAliI II. MUSSEY. 

